While exploring some futuristic ruins, Susan sees glimpses of a familiar girl.
- Bio-Augmentation: Besides having electronic brain implants, the Seekers have their organic bodies grown bigger and stronger thanks to "lessons" from a BrainComputer Interface.
- Call-Back: One of the founders on the island comes in a "MOCO" blimp, apparently from the pre-Mushroom War company BMO's creator ran.
- Chekhov's Gun: When Kara tries to consult Dr. Gross, she hides a piece of equipment she's working on. This turns out to be a Mind-Control Device for the Seekers that forces Susan to stop Frieda from leaving.
- Conflicting Loyalty: Kara is split between her duty as a Seeker, to keep everyone on the Island, and her friendship with Frieda, who wants to leave. She decides to help Frieda leave and seems to consider leaving with her, but Dr. Gross finds out and forces Susan to destroy Frieda's vehicle and take her to be re-educated.
- Crapsaccharine World: The human society is first introduced through a light-hearted song to Wide-Eyed Idealist kids, but later turned out to be a totalitarian state.
- Distracted by My Own Sexy: Kara/Susan at first objects to Frieda's holograms of her, but makes a sudden turnaround after Frieda's compliment.Kara: Wow, am I really that buff? I look great!
- Fantastic Caste System: Some of the island's inhabitants are raised from childhood for special roles as indicated by different-colored animal hats: "Seekers" (strong people who keep people on the island, usually by force, who wear purple), "Experimenters" (light blue), and "Helpers" (doctors and aid workers in white).
- Gilded Cage: The Islands are a fully-functional human society, but never let anyone leave.Kara: We're safe here.
Frieda: We have no freedom, Kara! I want to see what's out there!
Kara: It's all just bad stuff out there. You're only gonna get hurt.
Frieda: Maybe. But maybe getting hurt isn't the worst thing there is.
- Given Name Reveal: Turns out Susan's name on the Island was "Kara".
- Hidden Elf Village: The Islands is the last colony of humans that's locked away from the rest of the world and guarded by a Humongous Mecha guardian.
- I Have to Go Iron My Dog: When Kara notices the Frieda standing outside is just a hologram, she knocks out her desk, loudly claims she has to pee, and runs out the door to investigate. Dr. Gross falls for it.
- Obliviously Evil: The Seekers are so indoctrinated that they genuinely believe they're "helping" the hiders, even as they're capture them, beat them brutally, and drag them back to re-education.
- Saying Sound Effects Out Loud: When Martin is found trying to escape by Kara, he says "wink" as he winks in an attempt to charm her.
- Shout-Out: "Kara" for Kara Zor-El, second-to-last of her kind when we first meet her, or maybe Kara Thrace, a tough young woman who is forced to leave her home and becomes one of the last of a Dwindling Party of humans in the galaxy. Both happen to be blonde Distaff Counterparts of main characters Superman and Starbuck, respectively; Susan/Kara was introduced as a counterpart to Finn. "Kara Strong" could also be nod to voice actress Tara Strong.
- Swallowed Whole: Jake briefly swallows BMO whole when they fall on top of him.BMO: Huh. This was more fun in my dreams.